Selective area processing of InGaAsP

The electrical activation characteristics of Si⁺ and Be ⁺ ions implanted into InGaAsP (λ=1-3 μm) grown lattice-matched to InP by metalorganic molecular beam epitaxy were studied as a function of ion dose (5×10¹²-5×10 ¹⁴ cm^-2), annealing time (3-60 sec) and annealing temperature (575-750°C). Maximum doping concentrations of ~2×10¹⁹ cm^-3 were obtained for both Si⁺ and Be⁺, with activation energies for electrical activation of 0.58 eV and 0.39 eV, respectively. Multiple energy F⁺ or H⁺ implants can be used to produce high resistance layers for isolation purposes - maximum sheet resistances of ~8×10 ⁶ Ω/□ or ~10⁶ Ω/□ for initially p⁺ or n⁺InGaAsP, respectively, were obtained for F⁺ implants followed by annealing near 450°C. Smooth, anisotropic dry etching of the InGaAsP is obtained with electron cyclotron resonance CH₄/H₂/Ar discharges at low DC biases. The etch rates are the same for both n⁺ and p⁺ quaternary layers and are independent of the doping level